Digital transformation in ports requires more than the implementation of technological; it requires alignment between processes, people and technology. This study adopts a human-centred approach to analyse road gate operations at the Port of Sines during the transition to a Smart Gate ecosystem. A mixed methods approach combined process analysis, semi-structured interviews with nine transport companies, a questionnaire administered to 96 drivers, and preliminary validation of a mobile application prototype. The results highlight operational constraints related to infrastructure, communication, stakeholder awareness and systems interoperability. They also show that transport companies recognise the importance of digitalisation, despite differing readiness levels, whilst drivers show an overall positive attitude towards Smart Gate technologies. Based on these findings, the NaviGate app was conceptualised and validated as a user-centred digital solution to enhance communication, coordination and operational efficiency. The study contributes to understanding port digital transformation as a socio-technical, collaborative and progressive process.